1. Field of the Invention
The present invention relates to a sensitizer for a cinnamic acid photosensitive resin, and to a photosensitive composition thereof.
2. Description of the Prior Art
Various polymers containing the cinnamic acid radical prepared by polymerization reactions of cinnamic acid or cinnamic acid derivatives with other polymers have been proposed for use as photosensitive resins in various fields. In general, these photosensitive polymers have low photosensitivity. To improve the photosensitivity lower molecular weight sensitizer compounds have been added. Recently, increased sensitivity has been required for precise and high quality applications of cinnamic acid photosensitive resins. Spectral sensitization, that is expanded sensitive wavelengths, is insufficient, and improved sensitivity at any specific wavelength is required. For example, the photoresists used for preparation of IC, LSI and masks in the semiconductor field, are exposed by a projection printing system. In the system, a g-line (4358 A) is generally employed because of optical aberration. Accordingly, in this system, an increased sensitivity to the g-line is required. Sufficient increase of sensitivity is impossible with known sensitizers. A need exists therefore for a cinnamic acid photosensitive resin with high sensitivity.